The present invention relates to a novel brace for the knee portion of the leg which is particularly useful for patients recovering from ligament surgery.
It has been accepted in the medical field that use of a hinged knee brace is the best system to support a knee after ligament surgery. U.S. Pat. No. 4,523,585 discloses a novel hinge mechanism for such type of knee brace.
Anterior and posterior crucial ligaments (ACL and PCL) are often damaged during vigorous activities, such as sports. The most common ligament repair involves the ACL. This surgery involves the grafting or fixing of natural ligaments in place of the damaged ACL by an elaborate drilling and locating procedure. U.S. Pat. No. 4,712,542 describes such a ligament repair procedure.
It has been recognized that the rotation of the tibial and femoral portions of the leg about the knee is a very complex motion. Essentially, the knee involves a multiple axis rotation and translation. The latter motion has also been referred to as "drawer". Unfortunately, translation or drawer between the femoral and tibial portions of the leg tends to damage a freshly repaired ACL or PCL. It has been discovered anterior drawer or translation occurs in the human knee when the knee is extended between about 30.degree. of flexion and full extension (0.degree. of flexion). In other words, little or no translation takes place between full flexion of the knee (90.degree. ) and flexion to 30.degree. .
Although this problem has been recognized in the medical profession, solutions proposed to remedy the same have been less than satisfactory. For example, some prior art devices employ an elastic strap connected to uprights on the cuffs or elements which span the hinge mechanisms. Such elastic straps merely stiffen the connection of the cuff to the leg without preventing translation between the tibial and femoral leg portions on either side of the knee joint.
A knee brace which selectively prevents translation of the tibia and femur while permitting rotation therebetween would be a great advance in the medical field.